LOGAN, Utah — NASA is developing a larger payload adapter for cubesats flying on the next version of the Space Launch System, although it’s unclear if upcoming SLS launches will carry any such secondary payloads.
The inaugural flight of the SLS, the Artemis 1 mission that launched last November, carried 10 cubesats that were deployed after the release of the Orion spacecraft on an uncrewed test. NASA originally selected 13 cubesats to fly on Artemis 1 but three were not ready in time for payload integration in the fall of 2021.
All 13 selected cubesats were 6U spacecraft measuring approximately 10 by 20 by 30 centimeters, which at the time of their selection several years before launch was close to the state of the art for such smallsats. “A 6U cubesat was huge back in those days,” said David Hitt of Jacobs Space Exploration Group during an Aug. 10 presentation at the 37th Annual Conference on Small Satellites.
However, cubesats have grown larger since then to add additional capabilities like propulsion or to accommodate more advanced payloads. “Clearly we’ve got to elevate our capabilities there,” he said.
NASA has developed a new payload adapter for the Block 1B version of the SLS with the more powerful Exploration Upper Stage. That adapter, called the Nest, will have 15 payload mounting locations that can accommodate dispensers for 6U, 12U and 27U cubesats.
Exactly what size satellites can be included on the adapter, though, is still a work in progress, Hitt said, and will depend on feedback from satellite developers. “Maybe 27U won’t make sense to people. Maybe there’s somewhere in that range between 12 and 27 that makes more sense.”
The earliest the new Nest adapter would be used is the Artemis 5 launch, the second flight of the Block 1B version of the SLS scheduled for no earlier than 2029. There is currently no requirement to fly cubesats on the first Block 1B launch, Artemis 4 in 2028, he said.
Whether the remaining two Block 1 SLS missions, Artemis 2 and 3, will carry cubesats is still to be determined, he said. “We’re currently having internal discussions with [NASA] Headquarters about the near-term opportunities, so we’re still finalizing that.”
A paper accompanying the presentation noted that both Artemis 2 and Artemis 3 could carry cubesats. However, in the case of Artemis 2, both the upper stage and any secondary payloads released from it would be placed on a “high ballistic trajectory” that would put them on course for an Earth reentry within hours. Any cubesats deployed on Artemis 2, the paper stated, “would have an approximate eight-hour window to alter their trajectories, or they will follow the SLS upper stage on a high-altitude return trajectory.”
The paper added that Artemis 3 will likely offer several “bus stops” for deploying secondary payloads like on Artemis 1, which will be determined after the flight path is finalized. It said that cubesats flying on Artemis 3, scheduled for launch no earlier than the end of 2025, could be selected as soon as late summer or early fall of this year, based on the payload mass allocation for that mission, suitability for the Artemis 3 flight path, and NASA science, technology and exploration goals, among other factors.
The cubesats that flew on Artemis 1 had mixed results. Some reported partial or complete success, while many malfunctioned. Hitt noted in his presentation that, of the 10 cubesats on Artemis 1, eight did make contact after deployment and five at least partially achieved their mission goals.
Among those five was BioSentinel, billed as the first cubesat to perform biological research in deep space. In a conference presentation Aug. 7, Matthew Napoli of NASA’s Ames Research Center said the spacecraft was continuing to transmit data on the radiation environment nine months after its launch, 21 million kilometers from Earth. But cells on board did not show signs of growth after launch, which he said was likely because they had expired during the long wait before launch.
Another was LunaH-Map, a cubesat that was to go into orbit around the moon to look for water ice at the lunar poles. However, a stuck valve in the propulsion system on the cubesat prevented it from performing the maneuvers needed to reach that orbit. NASA announced Aug. 3 that the spacecraft has ceased operations after ending attempts to fix the faulty valve.
LunaH-Map was able to demonstrate the performance of its key instrument, a neutron spectrometer, collecting data during a flyby of the moon shortly after launch last November. “We are thrilled that the LunaH-Map team was able to use this opportunity to demonstrate the capability of its neutron spectrometer in flight, even though the mission could not be completed as planned,” Lori Glaze, director of NASA’s planetary science division, which funded development of LunaH-Map, said in a statement.
